1

Search for Microscopic Black Hole Signatures in the CMS Experiment

M. Savina on behalf of CMS Collaboration

CMS black hole working group: Brown University, USA: G. Landsberg, A. Ferapontov, P.K.V. Tsang

JINR, Russia: V. Konoplianikov , M. Savina, S. Shmatov

The NPD RAS Conference "The Physics of Fundamental Interactions", November 25, 2011, ITEP, Moscow

2

Pictures by Sabine Hossenfelder

In large extra dimension models• Gravity stronger at small distances• Horizon radius larger• For M ~ TeV it increases from 10-38 fm to 10-4 fm For these BH Rh<< R and they have approximately higher dimensional sphericalsymmetry

At the LHC partons can come closer than their Schwarzschild horizon

black hole production

3

Evolution stages for BHEvolution stages for BH

II-III. Hawking radiation phases (short spindown + more longer Schwarzschild) Quantum-mechanical decay trough tunneling, transition from Kerr spinning BH to stationary Schwarzschild one. angular momentum shedding (up to ~ 50% mass loss). Corrections with Gray Body Factors. After this – an entropy; thermal decay to all SM particles with BB energy spectra. Accelerating decay with a varying growing temperature. No flavor dependence, only numberof D.o.f.– “democratic” decay

IV. Planck phase: final explosion (subj for QGr)BH remnant (non-detectable energy losses), N-body decay, Q, B, color are conserved or not conserved

I. Balding phaseAsymmetric production, but “No hair” theorem: BH sheds its high multipole moments for fields (graviton and GB emitting classically), as electric charge and color.Characteristic time is about t ~ RS

Result: BH are classically stable objects. Inelasticity.

BH production in pp collisionsBH production in pp collisions BH production cross section(S. Dimopoulos, G. Landsberg, Phys.Rev.Lett.87:161602, 2001hep-ph/0106295v1)

PDF’s (MSTW2008lo68, CMS EXO-11-071)

ba ab

sM

aaa

a

sx

Mfxf

x

dx

s

M

dM

dL

,

2BH

1BH

BH 2BH

)(2

2BHˆ

BHBH

BH )BH(ˆMs

abdM

dL

dM

d

2SR

jiji

u ssy

xpp

QvufQvf

MnusrnFv

dvduzdzMdxs

M

,

1 21(

1

0min

),(),(

),,()(2,,,2

2)min

MMx BHmin

min sMy BH ˆmaxbbz

H. Yoshino and Y. Nambu, Phys. Rev. D 67, 024009(2003), gr-qc/0209003;L. A. Anchordoqui, J.L. Feng, H. Goldberg, and A.D. Shapere, hep-ph/0311365

Not all initial collision energy actually trapped during BH formation process

inelasticity – function of n,b

Democratic decay blinded to flavor: probabilities are the same for all species (violation of some conservation laws)

SBH must be large enough to reproduce thermal BH decay

(S.B. Giddings, hep-ph/0110127v3,K. Cheung, Phys. Rev. Lett. 88, 221602, 2002)

25 1

1 BH

BH

SS

K. Cheung, PR D66, 036007 (2002).

MM 5minBH

BH decay: Hawking temperature and entropyBH decay: Hawking temperature and entropy

S

n

BHH R

nnnn

M

MMT

4

1

4

1

23

8

2

1

1

Hawking temperature(R.C. Myers and M.J. Perry, Ann. Phys. 172, 304, 1986)

chS Rr )(

6

MBH >> MD : semiclassical well-defined description for BH’s.

What happens when MBH ~ MD?BH becomes “stringy”, their properties complex.

2minssBH gMM

22 )()(ssBHssSB gMMgMM

BHSB

Matching:

S. Dimopoulos and R. Emparan, Phys. Lett. B526, 393 (2002), hep-ph/0108060

K. Cheung, PR D66, 036007 (2002), hep-ph/0305003

BH specifity and experimental signaturesBH specifity and experimental signatures

7

• Potentially large cross sections (can be really suppressed by factors coming from production process details)

• Increasing cross sections with an energy, according to an absense of small gauge couplings

• High multiplicity of produced particles as proportional to a BH entropy

• Hard leptons and jets (high transverse momenta), in significant numbers

• Approximately thermally determined ratios of species (democratic decay)

• Relatively high sphericity for final states

8

9

CMS longitudinal view: one fourthCMS longitudinal view: one fourth

2ln

tg

Final state of the SM process vs typical BH Final state of the SM process vs typical BH decay spectradecay spectra

10

Multi-jet and hard leptons events High spherical High energy and pT

Pictures by Sabine Hossenfelder

SM ProcessBH decay

Experimental observables which are sensitive to these features

11

Electrons and photons: for barrel and

for end-cap

Muons: & pT > 20 GeV, Jets:

between any two objects

The multiplicity in the final state: Njet (number of jets) Under “jets” we assume individual hard objects like jets and also photons and leptons (e&μ)

Individual particle selection and cuts in the analysisIndividual particle selection and cuts in the analysis

44.1

4.256.1

5.022 R

1.2

6.2

12

sinEET

jetN

iTT ES

1

Scalar sum of the transverse energies of jetsScalar sum of the transverse energies of jets

CMS Detector simulation, the transverse view

CMS Detector simulation,the longitudinal view

Jets, photons and leptons, ET > 50 GeV

Missing ET > 50 GeV

13

CMS 3D real event visualisation, CMS 3D real event visualisation, N = 9 BH candidateN = 9 BH candidate

ST = 2.5 TeV (Run 165567, Event 347495624)

CMS Data, 2011

14

CMS real event visualisation: CMS real event visualisation: the transverse view, N = 10 BH candidatethe transverse view, N = 10 BH candidate

ST = 1.1 TeV (Run 163332, Event 196371106)

CMS Data, 2011

15

Low multiplicity regimeLow multiplicity regime (number of objects in FS N=2,3)(number of objects in FS N=2,3)

The CMS analysis 2011, 1.09 fb-1:CMS EXO-11-071

2N

3N

16

SSTT for events with N objects in FS for events with N objects in FS

The CMS analysis 2011, 1.09 fb-1:CMS EXO-11-0713N

4N

17

SSTT for events with N objects in FS for events with N objects in FS

The CMS analysis 2011, 1.09 fb-1:CMS EXO-11-071

5N6N

18

SSTT for events with N objects in FS for events with N objects in FS

The CMS analysis 2011, 1.09 fb-1:CMS EXO-11-0717N

8N

19

BH models without IS energy losses: Mmin is excluded up to 5.1 TeV for MPl up to 3.5 TeV at 95 % CL. (ADD-type scenarios)

20

String ball limits from the counting experiments for a set of model parameters (string coupling gs=0.4, fundamental scale Md and string scale Ms)

Mmin is excluded from 4.1 to 4.5 TeV at 95 % CL.

The CMS 2011, 1.09 fb-1:CMS EXO-11-071

SB(Mmin, Ms, Md)

Mmin > 2 Ms

gs = 0.4n = 6

(Md )n+2 =(Ms)n+2/gs

Md = Ms/0.79

Tmax =T0= Ms

BlackMax v2.01

String Ball LimitsString Ball Limits

21

Current resultsCurrent results,, statistics collected about 1.1 fb statistics collected about 1.1 fb-1-1::

Permanently renewable analysis for BH candidates in events with a large final multiplicity and a high sphericity (transverse energy sum for jets) Background estimation procedure (MC for EW contributions and “data-driven” method for QCD) For ADD-type models of BH and a number of scenarios (rotating&non-rotating, without IS losses) some limits have been established: 5.1 TeV for a minimal mass of BH and 3.5 TeV for a fundamental scale (be doubly careful when treat a lower region of BH masses near the fundamental scale). The first direct LHC limits for string ball production have been established: minimal mass of SB from 4.1 to 4.5 TeV have been excluded (depending on two scales – fundamental multidimensional and string one).

Important next steps (now and the end of this year, next 2012):Important next steps (now and the end of this year, next 2012):

Variety of BH models – energy losses during production stage and different parametrizations for losses, stable remnant, low multiplicity regimes, brane with a tension, etc. (MC study) Production near the fundamental threshold – breaking down of semiclassical treatment of BH, Quantum BH (MC ? + data)

Update for BH analysis with an integrated luminosity

22

Backup slidesBackup slides

BH Production in pp collisions at the LHCBH Production in pp collisions at the LHC

DL ‘01

For the LHC energies:

a) Parton-level productioncross section

b) Differential cross section

c) Hawking temperature

d) Average decay multiplicityfor Schwarzschild BH

n=4

(S. Dimopoulos, G. Landsberg, Phys.Rev.Lett.87:161602, 2001, hep-ph/0106295v1)

Exclusion Limits for ADD (virtual exc.)Exclusion Limits for ADD (virtual exc.)

Sergei Shmatov, Searches for Physics Beyond the Standard Model at the CMS Experiment, NPD RAS Conference 2011, Moscow 24

Dimuons

Diphotons CMS PAS EXO-11-038

CMS PAS EXO-11-039